Buried in that big ESPN.com story on the Miami Heat considering making a run at signing Carmelo Anthony was an item on LeBron James, businessman:

James' off-court business is booming, thanks to a string of investments paying off massively and the prospect of new opportunities in endorsements and entertainment projects promising to expand his wealth significantly in coming years.

In a recent example, while James was leading the Heat to a victory over the Indiana Pacers in the Eastern Conference finals, sources say the 29-year-old was finalizing what is believed to be the biggest equity cash payout for a professional athlete in history as part of Apple's recent $3 billion purchase of Beats Electronics. Sources briefed on the situation say James realized a profit of more than $30 million in cash and stock in the Beats sale after he had struck a deal to get a small stake in the company at its inception in 2008 in exchange for promoting its high-end headphones.

In Beats' formative months, nothing was better for business than the U.S. Olympic basketball team being seen wearing them. (James had been given a prototype pair by Jimmy Iovine, and served as the middleman to hook up the rest of Team USA. The rest of the sports world soon followed: "I started hearing from people who wanted to know: What are they?" James said. "Where did I get them?")

As it turned out, James had an endorsement deal with Beats, but it wasn't the standard you-pay-me-to-advertise-the-product contract. Instead, James was given a stake in the company—about one percent, if the ESPN report is accurate.

It makes sense, at least for those athletes well-paid enough to assume the risk of investing. The potential payout can dwarf that of a simple licensing deal—compare James's windfall from Beats (which still leaves him with a good amount of Apple stock) with the reported $4 million annually he gets from McDonald's on a traditional endorsement deal. And on the company's end, it's doubly smart: Not only does the athlete have a concrete stake (both emotional and financial) in the company's success, but since compensation is directly tied to the company's growth, it's a win-win situation.